IR: Split out countUnresolvedOperands(), NFC

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@226508 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/IR/Metadata.h

@@ -843,6 +843,7 @@ private:
   void resolve();
   void resolveAfterOperandChange(Metadata *Old, Metadata *New);
   void decrementUnresolvedOperandCount();
+  unsigned countUnresolvedOperands() const;
 
   void deleteAsSubclass();
   UniquableMDNode *uniquify();